The present invention relates to a vented hatch cover for railroad cars. More specifically, it relates to a vented hatch cover for railroad cars having air filtering mechanisms.
Railroad hopper cars carrying bulk particulate matter, such as grain or plastic pellets, are typically unloaded by applying a vacuum conveying line to an outlet gate positioned at the bottom of each car compartment. The primary air flow for the vacuum conveying line is obtained from the exterior of the car. However, the rate of content removal results in reduction in pressure above the lading. The top of the car compartment must be vented to compensate for material drawn out the bottom of the compartment. Failure to vent the top of the compartment would reduce the efficiency of the vacuum unloading process and even risk damage to the car structure.
Vented hatch covers are known. They represent a successful solution to the prior deficiencies. Such covers are available from Salco Products Inc., Lemont, Ill. The vented hatch covers successfully marketed by Salco Products have downwardly or inwardly directed vent openings which are protected from the elements. These configurations are disclosed in U.S. Pat. Nos. 4,819,830; 5,064,089 and 5,622,177, the disclosures of which are incorporated herein by reference. The present invention represents a refinement in the vented hatch covers of the type in U.S. Pat. Nos. 4,819,830; 4,964,089 and 5,622,177. The vented hatch cover of the present invention provides the benefits of easy and quick installation and removal of the intake and discharge filter elements. The vented hatch cover of the present invention further provides the benefit of added rigidity to the walls defining the intake passage to prevent the walls from collapsing toward each other or expanding away from each other. This added rigidity to the walls ensures that the air intake passage maintain the full open area.